As used herein, the term "card" refers to any type of credit card or credit account mechanism including, but not limited to: a) a telephone-company-issued card, such as the Bell Atlantic IQ Card, b) a combined commercial credit card and telephone card, such as the AT&T Universal Card, c) a commercial credit card, such as an American Express card or a VISA card, or d) a debit card. A "card number" is a multi-character string that identifies the account associated with a card. A "card call" is a telephone call whose cost is charged to the account associated with a card. Other common ways of referring to a "card call" are: a) a call charged to a card, or b) a call charged to a card number. It will be appreciated that card issuers, i.e., the providers of the credit for each card, need not provide a tangible manifestation, such as embossed plastic, for each card.
Using a card call as an example, currently, a caller who places a call to be charged to a card must enter all of the digits of his card number and the associated personal identification number (PIN), if any, for each such call. It is noted that, depending on one's perspective, the characters comprising a PIN may or may not be considered as an integral part of the card number. Either way, however, there is a single piece of information, usually the PIN, which the issuer believes only an authorized user of the card would know, and this authentication information must be supplied before a card call, or any transaction charged to a card, is permitted to proceed.
The advantages of such a system are 1) that it is easy to ubiquitously implement at low cost, through the use of telephone dial pads and dual tone, multi-frequency signaling (DTMF), because the card number and authentication information are all sets of letters or digits and 2) the authorized user need not remember a large amount of information that he didn't already know. However, a drawback of such a system is that the card number and the PIN may be stolen by an unscrupulous person who observes their entry by a caller at a telephone key pad. The thief can then make calls and charge them to the card, by supplying the stolen card number and PIN. Theft of service may continue until the unusual calling pattern is noticed by the card owner or the card issuer and the card number and/or PIN is changed.
Well known prior art solutions to overcome this drawback have proposed that information representing measurements of various physical characteristics of an authorized person, such as voice prints, finger prints, retina patterns, etc., be used as authentication information in conjunction with, or instead of, the PIN. While measurement of physical characteristics for authentication can greatly reduce the fraud problem, there remain technological and cost obstacles to incorporating this technique in a generally available fraud prevention system.